class A:
    def a(self):
        print('----ac---')
    def b(self):
        print('.....ad...')
class B:
    def a(self):
        print('_____ax_______')
    def b(self):
        print(',,,,avu,,,')
class D:
    def a(self):
        print('cai')
class C(D,B,A):
    pass
c=C()
c.b()